A clamping plate or strut of the above type is described in the specification of French published patent application FR 2 668 242A. This known type of strut is intended for joining, to a component of an air conditioning installation, the free ends of the inlet and outlet tubes of an evaporator, which are joined together at their other ends by the evaporator itself, and which are arranged one above the other. In the strut described in that specification, the two apertures are in the form of slots, each of which is open in a respective one of the opposed ends of the strut. In order to prevent the strut from becoming separated from the tubes when it is disassembled from the condenser (in which case it might fall out of reach), the sides of the notches defined by the slots are inclined with respect to the plane which contains the axis of the semicircular base portions of the apertures.